The standby switch in my Jet City JCA2112RC seems to have crapped out. It felt like it was stuck when I tried to turn it off, and didn't feel like the normal click. The amp gets no sound now no matter what (replaced all the tubes and kept trying, tested the speaker using another head).

The standby toggle is a DPDT being used as a DPST. One side of it will not turn on, but the other will (tested with the continuity function on my VOM).

So here's my question: can I use a Carling 0822R switch to replace it? I have one that came as the power toggle on my Fender Blues Jr (I replaced it with a BillM mod off-standby-on toggle switch; the original switch is a DPST that was used on the mains).

The Jet City switch has an odd amperage rating on it, not only because the numbers are so high, but also because the 250V figure is not double the 125V. It says "15A 125V, 20A 250V."

The Carling switch from the Fender (and all of the DPST standby toggle replacement switches at AntiqueElectronicSupply) is rated "3A 250VAC, 6A 125VAC."

The Jet City amp is the combo/reverb version of the JCA20. Solid state rectifier. Two heavy red wires coming off the PT go to this standby switch, two slightly thinner red wires go to the PCB so I assume this switch is before the rectifier.

Nuts. I don't seem to see any available like that. Spade terminals preferably. I emailed Jet City customer service but I'm not sure what kind of repair network they have since these are manufactured overseas.

OK maybe it's academic. Jet City customer service just replied by email (on a Sunday afternoon) offering to mail me a replacement switch.

Thanks, though, Micky, you kept me from temporarily using the wrong switch.

And if anybody's listening, the Jet City amp was constructed by soldering the wires onto quick-connect (spade) terminals on the standby switch, instead of using crimp-spade connectors, with shrink-wrap over each connection. the mains power switch has a combination of quick-connect (with clear shrink-wrap) and soldered (black shrink-wrap) connections.

Sorry I didn't get to this sooner. but glad you got it sorted.
This is the kind of thing people need to see, not only to prevent damage to their equipment but to prevent injury to themselves or others. Generally on most schematics, the hi-voltage or special order parts are noted, so that the exact replacement can be fitted. With a standby switch such as this, it is critical to replace with a same-rated component, especially when switching high voltage.

The other thing is, people shouldn't be afraid to contact the manufacturer. It generally works out well.

Since intermittent problems are so hard to diagnose, I took apart the old standby switch. there were some loose shards of plastic floating around inside that must have jammed the metal contacts. The actuator broke just enough to shower pieces into the works, but not enough for it to come loose from the end of the toggle.

So I'm glad to know for sure that this switch was the problem. Mind you, it doesn't sound like a Marshall, but it's really not supposed to anyway.